Total chewing gum manufacture using high efficiency continuous mixing having optimized feed openings

ABSTRACT

A method is provided for the manufacture of chewing gum on a continuous basis. The method uses a continuous high efficiency mixer which is configured for the total manufacture of a wide variety of chewing gum products and includes at least one ingredient feed opening that is enlarged.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.08/362,254, filed on Dec. 22, 1994, now U.S. Pat. No. 5,543,160, whichis a continuation-in-part of U.S. application Ser. No. 08/305,363, filedon Sep. 13, 1994, now abandoned.

FIELD OF THE INVENTION

This invention is a process for the total manufacture of chewing gumbase and chewing gum using a single high efficiency continuous mixer.

BACKGROUND OF THE INVENTION

Conventionally, chewing gum base and chewing gum product have beenmanufactured using separate mixers, different mixing technologies and,often, at different factories. One reason for this is that the optimumconditions for manufacturing gum base, and for manufacturing chewing gumfrom gum base and other ingredients such as sweeteners and flavors, areso different that it has been impractical to integrate both tasks.Chewing gum base manufacture, on the one hand, involves the dispersive(often high shear) mixing of difficult-to-blend ingredients such aselastomer, filler, elastomer plasticizer, base softeners/emulsifiersand, sometimes wax, and typically requires long mixing times. Chewinggum product manufacture, on the other hand, involves combining the gumbase with more delicate ingredients such as product softeners, bulksweeteners, high intensity sweeteners and flavoring agents usingdistributive (generally lower shear) mixing, for shorter periods.

In order to improve the efficiency of gum base and gum productmanufacture, there has been a trend toward the continuous manufacture ofchewing gum bases and products. U.S. Pat. No. 3,995,064, issued toEhrgott et al., discloses the continuous manufacture of gum base using asequence of mixers or a single variable mixer. U.S. Pat. No. 4,459,311,issued to DeTora et al., also discloses the continuous manufacture ofgum base using a sequence of mixers. Other continuous gum basemanufacturing processes are disclosed in European Publication No.0,273,809 (General Foods France) and in French Publication No. 2,635,441(General Foods France).

U.S. Pat. No. 5,045,325, issued to Lesko et al., and U.S. Pat. No.4,555,407, issued to Kramer et al., disclose processes for thecontinuous production of chewing gum products. In each case, however,the gum base is initially prepared separately and is simply added intothe process. U.S. Pat. No. 4,968,511, issued to D'Amelia et al.,discloses a chewing gum product containing certain vinyl polymers whichcan be produced in a direct one-step process not requiring separatemanufacture of gum base. However, the disclosure focuses on batch mixingprocesses not having the efficiency and product consistency achievedwith continuous mixing. Also, the single-step processes are limited tochewing gums containing unconventional bases which lack elastomers andother critical ingredients.

In order to simplify and minimize the cost of chewing gum manufacture,there is need or desire in the chewing gum industry for an integratedcontinuous manufacturing process having the ability to combine chewinggum base ingredients and other chewing gum ingredients in a singlemixer, which can be used to manufacture a wide variety of chewing gums.

SUMMARY OF THE INVENTION

The present invention provides methods for the continuous manufacture ofa wide variety of chewing gum products using high efficiency mixers.

Pursuant to the present invention, at least certain ingredient feed portopenings of a high efficiency mixer are optimized. In this regard, atleast certain of the ingredient feed openings are optimized so as toallow: smaller pumps to be used; higher viscosity fluids to be added;lower temperature of ingredients to be fed into the mixer; and/or ahigher throughputs of ingredients.

To this end, in an embodiment, the present invention provides a methodfor manufacturing chewing gum using a high efficiency continuous mixercomprising the steps of: providing a high efficiency continuous mixerthat includes ingredient addition ports having openings; enlarging atleast one of the openings of one of the ingredient addition ports;adding gum base ingredients to the mixer; adding flavor and sweetener tothe mixer; and wherein at least one of the ingredients is added throughthe enlarged opening.

In an embodiment of the method, the gum base is added as finished gumbase to the mixer.

In an embodiment of the method, the opening is enlarged sufficiently toallow the ingredient to be added without the ingredient being heated.

In an embodiment of the method, the opening of a feed nozzle isenlarged.

In an embodiment of the method, the opening of an injection port isenlarged.

In another embodiment, the present invention provides a method ofcontinuously manufacturing chewing gum comprising the steps of: a)adding gum base ingredients into a high efficiency continuous mixer; b)adding at least one sweetener and at least one flavor into thecontinuous mixer, and mixing said sweetener and flavor with theremaining ingredients to form a chewing gum product; and c) wherein atleast one ingredient is added into the mixer using a piston pump.

In still another embodiment, the present invention provides a method ofcontinuously manufacturing chewing gum comprising the steps of: a)adding gum base ingredients into a high efficiency continuous mixer; b)adding at least one sweetener and at least one flavor into thecontinuous mixer, and mixing said sweetener and flavor with theremaining ingredients to form a chewing gum product; and c) wherein atleast one ingredient is added into the mixer using a gear pump.

In yet a further embodiment, the present invention provides a method ofcontinuously manufacturing chewing gum comprising the steps of: a)adding gum base ingredients into a high efficiency continuous mixer; b)adding at least one sweetener and at least one flavor into thecontinuous mixer, and mixing said sweetener and flavor with theremaining ingredients to form a chewing gum product; and c) wherein atleast one ingredient is added into the mixer using a diaphragm pump.

In a further embodiment, the present invention provides a method ofcontinuously manufacturing chewing gum without requiring separatemanufacture of a chewing gum base, comprising the steps of: a) adding atleast an elastomer and filler into a high efficiency continuous mixer;b) adding at least one sweetener and at least one flavoring agent intothe elastomer and filler in the continuous mixer; and c) wherein atleast one ingredient is added through an opening of the mixer that hasbeen enlarged by at least 10% as compared to a similar opening in astandard mixer.

In a further embodiment, the present invention provides a method ofmodifying a high efficiency continuous mixer for continuouslymanufacturing chewing gum comprising the steps of enlarging at least oneopening of an ingredient feed port of the mixer.

The present invention also provides chewing gum made by the methods ofthe present invention.

Pursuant to the present invention, a high efficiency continuous mixer isused. A high efficiency continuous mixer is one which is capable ofproviding thorough mixing over a relatively short distance or length ofthe mixer. This distance is expressed as a ratio of the length of aparticular active region of the mixer screw, which is composed of mixingelements, divided by the maximum diameter of the mixer barrel in thisactive region.

In an embodiment, the method of the invention can comprise performingthe following mixing steps in a single continuous mixer:

-   -   a) adding and thoroughly mixing at least a portion of the        chewing gum base ingredients (elastomer, elastomer plasticizer,        filler, etc.) in a continuous mixer, using an L/D of not more        than about 25;    -   b) adding at least a portion of the remaining (non-base) chewing        gum ingredients (sweeteners, flavors, softeners, etc.), and        thoroughly mixing these ingredients with the gum base in the        same mixer, using an L/D of not more than about 15; and    -   c) sufficiently completing the entire addition and mixing        operation in the same mixer, so that the ingredients exist as a        substantially homogeneous chewing gum mass, using a total L/D of        not more than about 40.

It is preferred that the gum base ingredients be completely added andmixed upstream from the remaining chewing gum ingredients, and that theremaining ingredients be completely added downstream for mixing with thealready blended gum base. However, the invention also includes thosevariations wherein a portion of the gum base ingredients may be addeddownstream with or after some of the remaining ingredients, and/orwherein a portion of the remaining (non-base) ingredients are addedupstream with or before some of the base ingredients. In an embodiment,a substantially homogenous chewing gum product mass is formed in asingle continuous mixer, using an L/D of not more than about 40, withoutrequiring a separate mixer to manufacture the chewing gum base.

With the foregoing in mind, in an embodiment, it is an advantage of theinvention to provide a continuous method for manufacturing chewing gumwhich does not require a separate manufacture of chewing gum base.

It is an advantage of the invention to provide a method formanufacturing chewing gum using an extruder that has maximized pin/portnozzle openings.

It is an advantage of the invention to provide a method formanufacturing chewing gum using an extruder that allows smaller pumps tobe used for feeding ingredients into the extruder.

It is an advantage of the invention to provide a method formanufacturing chewing gum that allows-high viscosity fluids to be fedthrough the ports into the mixer.

It is an advantage of the present invention to provide a method thatallows ingredients at lower temperatures to be fed into the mixer.

It is an advantage of the invention to allow higher throughputs ofingredients to be achieved.

It is also an advantage, in an embodiment of the invention, to provide acontinuous method for making chewing gum which accomplishes everyessential mixing step using a single mixer.

It is also an advantage of the invention to provide a continuous methodfor making chewing gum which requires less equipment, less capitalinvestment, and less labor than conventional manufacturing methods.

It is also an advantage of the invention to provide a continuousmanufacturing method that produces chewing gum having greater productconsistency, less thermal degradation, less thermal history, and lesscontamination than chewing gum produced using conventional processesthat require longer manufacturing times and more manufacturing steps.

The foregoing and other features and advantages of the invention willbecome further apparent from the following detailed description of thepresently preferred embodiments, read in conjunction with theaccompanying examples and drawings. The detailed description, examplesand drawings are intended to be merely illustrative rather thanlimiting, the scope of the invention being defined by the appendedclaims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial exploded perspective view of a Buss high efficiencymixer illustrating a mixing barrel and mixing screw arrangement.

FIG. 2A is a perspective view of an on-screw element used on theupstream side of a restriction ring assembly, in the high efficiencymixer configuration.

FIG. 2B is a perspective view of an on-screw element used on thedownstream side of the restriction ring assembly in the high efficiencymixer configuration.

FIG. 2C is a perspective view of a restriction ring assembly used in thehigh efficiency mixer configuration.

FIG. 3 is a perspective view showing the relative positioning of theelements of FIGS. 2A, 2B and 2C in the high efficiency mixerconfiguration.

FIG. 4 is a perspective view of a low-shear mixing screw element used inthe high efficiency mixer configuration.

FIG. 5 is a perspective view of a high-shear mixing screw element usedin the high efficiency mixer configuration.

FIG. 6 is a perspective view of a barrel pin element used in the highefficiency mixer configuration.

FIG. 7 is a schematic diagram of an arrangement of mixing barrel pinsand ingredient feed ports.

FIG. 8 is a schematic diagram of a mixing screw configuration.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The present invention provides methods for the manufacture of chewinggum. In an embodiment, the present invention allows for the totalmanufacture of chewing gum using a single continuous high-efficiencymixer, without requiring the separate manufacture of chewing gum base.

The methods of the present invention can be advantageously performedusing a continuous mixer whose mixing screw is composed primarily ofprecisely arranged mixing elements with only a minor fraction of simpleconveying elements. A presently preferred mixer is a blade-and-pin mixerexemplified in FIG. 1. A blade-and-pin mixer uses a combination ofselectively configured rotating mixer blades and stationary barrel pinsto provide efficient mixing over a relatively short distance. Acommercially available blade-and-pin mixer is the Buss kneader,manufactured by Buss AG in Switzerland, and available from Buss America,located in Bloomingdale, Ill.

In continuous high efficiency mixers, liquid ingredients can be fedusing gravimetric or volumetric pumps into the large feed ports and/orsmaller liquid injection ports. The injection ports and feed ports allowingredients to be fed into the mixer where they can be compounded into aproduct, e.g., chewing gum. However, it has been found in manufacturingchewing gum that due to the size of the injection pin opening and nozzleopening, the ingredients may not be fed efficiently into the extruder.

If the feed openings are too small, excessive pressure will build upwithin the system. The ingredients will then be fed at an inadequaterate. This will also cause the pump to overload. On the other hand, ifthe openings are too large, it has been found that there will be aninconsistent feeding period. This can also result in a clogging.

It has also been discovered that by maximizing the openings of theinjection pins or port nozzles, smaller pumps can be utilized to injectthe ingredients therethrough. Additionally, pursuant to the presentinvention, by maximizing the openings of these pin/port nozzles, higherviscosity fluids can be used, lower temperatures of ingredients can beused and/or higher throughputs can be achieved. In this regard, theenlarged openings allow such ingredients to be fed therethrough.

Pursuant to the present invention, the feed openings or pin openings areoptimized. With respect to the injection pins, these openings areenlarged as compared to the standard openings. As used herein, the term“standard openings” refer to the size of a port opening on a continuousmixer that is commercially available as of the filing date of thispatent application from Buss America. Preferably, the opening isenlarged by at least approximately 5% to about 95% of an equivalentlypositioned “standard opening.” In a preferred embodiment, the opening isenlarged by at least approximately 10% to about 90% of the standardopening. And most preferably, the opening is enlarged from approximately20% to about 80% of the standard opening.

Either the port nozzles or pin openings (injection pins), or both, canbe enlarged pursuant to the present invention. One method for sizing theopenings of the injection pin is to use a high speed electric drill. Tothis end, the injection pin is removed from the extruder and the openingis drilled gradually until the desired diameter of the opening isachieved. It is important to size the pin properly because excessiveremoval of the metal within the pin can result in pin failure. It shouldbe noted that in some extruders, the injection pins usually have aworking mechanism within them to prevent the pin from clogging. Thismechanism should be removed from the pin to create desired feed ratesand sizing of the opening.

In the case of feed nozzles, which are used to add greater volumes ofliquid to larger ingredient addition ports, the nozzle openings aresized by removing the existing injection nozzle and attaching a largernozzle.

To determine the optimal size of the openings, the ingredient additionport openings are enlarged until the pump, that is pumping theingredients, maintains a normal operating pressure or desired velocity.Or, the openings are enlarged until the desired velocity of product isachieved.

It is known in adding ingredients to a mixer that the ingredients can beheated. Heating ingredients can compensate for too small an orifice.However, heat can damage sensitive ingredients and result in anundesirable product.

Therefore, it may be desirable to not heat at least certain ingredients.Further, minimizing the temperature of individual ingredients or blendsof ingredients can lower the internal mixing temperature. This can beused to prevent sensitive ingredients from degregation. This also lowersthe temperature of the chewing gum product exiting the extruder whichalso protects the ingredients from degregation. By maximizing theingredient feed openings, cooler ingredients can be added to the mixer.

Pursuant to the present invention, a number of liquid ingredients can beadded through these injection pins and nozzle openings which areoptimized. These ingredients include: corn syrup; hydrogenated syruphydrolysates; flavors; glycerin; liquid suspensions of sweeteners orhigh intensity sweeteners; acids; lower molecular weightpolyisobutylene; sorbitol solutions or liquids of liquid alditols; fats;oils; lipids; waxes; and any other liquid ingredient or combinations ofingredients.

Additionally, the present invention allows smaller pumps to be used tofeed the ingredients into the extruder through the openings. To thisend, the ingredients can be pumped into the extruder using a pistonpump, gear pump, or diaphragm pump.

A piston pump works by pulling back within its cylinder and therebydrawing liquid ingredients into the cylinder. The piston is then pushedback into the cylinder pushing the ingredients forward through the pinand into the extruder. It has been found that it is preferred thatflavor be pumped with a piston pump at room temperature or cooler. Lowmolecular weight rubber, such as polyisobutylene and syrups, it has beenfound, are preferably pumped with gear pumps at 250° F. and 100° F.,respectively.

A gear pump works by securing the ingredient with the teeth of the gear.The pump then pushes the ingredient forward as the gear turns. Anexample of a gear pump is the MAAG Thermoinox® gear pump. It has beenfound that low molecular weight rubber, such as polyisobutylene andsyrups, are preferably pumped with gear pumps at 250° F. and 100° F.,respectively.

Diaphragm pumps work similar to the piston pump. However, in thediaphragm pump, there is a flat sheet of plastic that moves back andforth instead of the piston moving the ingredient into the extruder. Ithas also been found that preferably fats are pumped using a diaphragmpump at 225° F.

Referring to FIG. 1, the blade-and-pin mixer 100 includes a singlemixing screw 120 turning inside a barrel 140 which, during use, isgenerally closed and completely surrounds the mixing screw 120. Themixing screw 120 includes a generally cylindrical shaft 122 and threerows of mixing blades 124 arranged at evenly spaced locations around thescrew shaft 122 (with only two of the rows being visible in FIG. 1). Themixing blades 124 protrude radially outward from the shaft 122, witheach one resembling the blade of an axe.

The mixing barrel 140 includes an inner barrel housing 142 which isgenerally cylindrical when the barrel 140 is closed around the screw 120during operation of the mixer 100. Three rows of stationary pins 144 arearranged at evenly spaced locations around the screw shaft 142, andprotrude radially inward from the barrel housing 142. The pins 144 aregenerally cylindrical in shape, and may have rounded or bevelled ends146.

The mixing screw 120 with blades 124 rotates inside the barrel 140 andis driven by a variable speed motor (not shown). During rotation, themixing screw 120 also moves back and forth in an axial direction,creating a combination of rotational and axial mixing which is highlyefficient. During mixing, the mixing blades 124 continually pass betweenthe stationary pins 144, yet the blades and the pins never touch eachother. Also, the radial edges 126 of the blades 124 never touch thebarrel inner surface 142, and the ends 146 of the pins 144 never touchthe mixing screw shaft 122.

FIGS. 2–6 illustrate various screw elements which can be used toconfigure the mixing screw 120 for optimum use. FIGS. 2A and 2Billustrate on-screw elements 20 and 21 which are used in conjunctionwith a restriction ring assembly. The on-screw elements 20 and 21 eachinclude a cylindrical outer surface 22, a plurality of blades 24projecting outward from the surface 22, and an inner opening 26 with akeyway 28 for receiving and engaging a mixing screw shaft (not shown).The second on-screw element 21 is about twice as long as the firston-screw element 20.

FIG. 2C illustrates a restriction ring assembly 30 used to build backpressure at selected locations along the mixing screw 120. Therestriction ring assembly 30 includes two halves 37 and 39 mounted tothe barrel housing 142, which halves engage during use to form a closedring. The restriction ring assembly 30 includes a circular outer rim 32,an inner ring 34 angled as shown, and an opening 36 in the inner ringwhich receives, but does not touch, the on-screw elements 20 and 21mounted to the screw shaft. Mounting openings 35 in the surface 32 ofboth halves of the restriction ring assembly 30 are used to mount thehalves to the barrel housing 142.

FIG. 3 illustrates the relationship between the restriction ringassembly 30 and the on-screw elements 20 and 21 during operation. Whenthe mixing screw 120 is turning inside the barrel 140, and reciprocatingaxially, the clearances between the on-screw elements 20 and 21 and theinner ring 34 provide the primary means of passage of material from oneside of the restriction ring assembly 30 to the other. The on-screwelement 20 on the upstream side of the restriction ring assemblyincludes a modified blade 27 permitting clearance of the inner ring 34.The other on-screw element 21 is placed generally downstream of therestriction ring assembly 30, and has an end blade (not visible) whichmoves close to and wipes the opposite surface of the inner ring 34.

The clearances between outer surfaces 22 of the on-screw elements 20 and21 and the inner ring 34 of the restriction ring assembly 30, which canvary and preferably are on the order of 1–5 mm, determine to a largeextent how much pressure build-up will occur in the upstream region ofthe restriction ring assembly 30 during operation of the mixer 100. Itshould be noted that the upstream on-screw element 20 has an L/D ofabout ⅓, and the downstream on-screw element 21 has an L/D of about ⅔,resulting in a total L/D of about 1.0 for the on-screw elements. Therestriction ring assembly 30 has a smaller L/D of about 0.45 whichcoincides with the L/D of the on-screw elements 20 and 21, which engageeach other but do not touch the restriction ring assembly.

FIGS. 4 and 5 illustrate the mixing or “kneading” elements which performmost of the mixing work. The primary difference between the lower shearmixing element 40 of FIG. 4 and the higher shear mixing element 50 ofFIG. 5 is the size of the mixing blades which project outward on themixing elements. In FIG. 5, the higher shear mixing blades 54 whichproject outward from the surface 52 are larger and thicker than thelower shear mixing blades 44 projecting outward from the surface 42 inFIG. 4. For each of the mixing elements 40 and 50, the mixing blades arearranged in three circumferentially-spaced rows, as explained above withrespect to FIG. 1. The use of thicker mixing blades 54 in FIG. 5 meansthat there is less axial distance between the blades and also lessclearance between the blades 54 and the stationary pins 144 as the screw120 rotates and reciprocates axially (FIG. 1). This reduction inclearance causes inherently higher shear in the vicinity of the mixingelements 50.

FIG. 6 illustrates a single stationary pin 144 detached from the barrel140. The pin 144 includes a threaded base 145 which permits attachmentat selected locations along the inner barrel shaft 142. It is alsopossible to configure some of the pins 144 as liquid injection ports byproviding them with hollow center openings.

FIG. 7 is a schematic view showing a presently preferred barrelconfiguration, including a presently preferred arrangement of barrelpins 144.

FIG. 8 is a corresponding schematic view illustrating a presentlypreferred mixing screw configuration. The mixer 200 whose preferredconfiguration is illustrated in FIGS. 7 and 8 has an overall activemixing L/D of about 19.

The mixer 200 includes an initial feed zone 210 and five mixing zones220, 230, 240, 250 and 260. The zones 210, 230, 240, 250 and 260 includefive possible large feed ports 212, 232, 242, 252 and 262, respectively,which can be used to add major (e.g. solid) ingredients to the mixer200. The zones 240 and 260 are also configured with five smaller liquidinjection ports 241, 243, 261, 263 and 264 which are used to add liquidingredients. The liquid injection ports 241, 243, 261, 263 and 264include special barrel pins 144 formed with hollow centers, as explainedabove. As also noted above, each of the openings of the large feed ports212, 232, 242, 252, and 262 and small liquid injection ports 241, 243,261, 263, and 244 can be optimized.

Referring to FIG. 7, barrel pins 144 are preferably present in most orall of the available locations, in all three rows as shown.

Referring to FIG. 8, a presently preferred configuration of the mixingscrew 120 for most chewing gum products is schematically illustrated asfollows. Zone 210, which is the initial feed zone, is configured withabout 1⅓ L/D of low shear elements, such as the element 40 shown in FIG.4. The L/D of the initial feed zone 210 is not counted as part of theoverall active mixing L/D of 19, discussed above, because its purpose ismerely to convey ingredients into the mixing zones.

The first mixing zone 220 is configured, from left to right (FIG. 8),with two low shear mixing elements 40 (FIG. 4) followed by two highshear elements 50 (FIG. 5). The two low shear mixing elements contributeabout 1⅓ L/D of mixing, and the two high shear mixing elementscontribute about 1⅓ L/D of mixing. Zone 220 has a total mixing L/D ofabout 3.0, including the end part covered by a 57 mm restriction ringassembly 30 with cooperating on-screw elements 20 and 21 (not separatelydesignated in FIG. 8).

The restriction ring assembly 30 with cooperating on-screw elements 20and 21, straddling the end of the first mixing zone 220 and the start ofthe second mixing zone 230, have a combined L/D of about 1.0, part ofwhich is in the second mixing zone 230. Then, zone 230 is configured,from left to right, with three low shear mixing elements 40 and 1.5 highshear mixing elements 50. The three low shear mixing elements contributeabout 2.0 L/D of mixing, and the 1.5 high shear mixing elementscontribute about 1.0 L/D of mixing. Zone 230 has a total mixing L/D ofabout 4.0.

Straddling the end of the second mixing zone 230 and the start of thethird mixing zone 240 is a 60 mm restriction ring assembly 30 withcooperating on-screw elements 20 and 21 having an L/D of about 1.0.Then, zone 240 is configured, from left to right, with 4.5 high shearmixing elements 50 contributing a mixing L/D of about 3.0. Zone 240 alsohas a total mixing L/D of about 4.0.

Straddling the end of the third mixing zone 240 and the start of thefourth mixing zone 250 is another 60 mm restriction ring assembly 30with cooperating on-screw elements having an L/D of about 1.0. Then, theremainder of the fourth mixing zone 250 and the fifth mixing zone 260are configured with eleven low shear mixing elements 40 contributing amixing L/D of about 7⅓. Zone 250 has a total mixing L/D of about 4.0,and zone 260 has a total mixing L/D of about 4.0.

Before explaining where the various chewing gum ingredients are added tothe continuous mixer 200, and how they are mixed, it is helpful todiscuss the composition of typical chewing gums that can be made usingthe methods of the invention. A chewing gum generally includes a watersoluble bulk portion, a water insoluble chewing gum base portion, andone or more flavoring agents. The water soluble portion dissipates overa period of time during chewing. The gum base portion is retained in themouth throughout the chewing process.

The insoluble gum base generally includes elastomers, elastomerplasticizers (resins), fats, oils, waxes, softeners and inorganicfillers. The elastomers may include polyisobutylene,isobutylene-isoprene copolymer, styrene butadiene copolymer and naturallatexes such as chicle. The resins may include polyvinyl acetate andterpene resins. Low molecular weight polyvinyl acetate is a preferredresin. Fats and oils may include animal fats such as lard and tallow,vegetable oils such as soybean and cottonseed oils, hydrogenated andpartially hydrogenated vegetable oils, and cocoa butter. Commonly usedwaxes include petroleum waxes such as paraffin and microcrystalline wax,natural waxes such as beeswax, candellia, carnauba and polyethylene wax.

The gum base typically also includes a filler component such as calciumcarbonate, magnesium carbonate, talc, dicalcium phosphate and the like;softeners, including glycerol monostearate and glycerol triacetate; andoptional ingredients such as antioxidants, color and emulsifiers. Thegum base constitutes between 5–95% by weight of the chewing gumcomposition, more typically 10–50% by weight of the chewing gum, andmost commonly 20–30% by weight of the chewing gum.

The water soluble portion of the chewing gum may include softeners, bulksweeteners, high intensity sweeteners, flavoring agents and combinationsthereof. Softeners are added to the chewing gum in order to optimize thechewability and mouth feel of the gum. The softeners, which are alsoknown as plasticizers or plasticizing agents, generally constitutebetween about 0.5–15% by weight of the chewing gum. The softeners mayinclude glycerin, lecithin, and combinations thereof. Aqueous sweetenersolutions such as those containing sorbitol, hydrogenated starchhydrolysates, corn syrup and combinations thereof, may also be used assofteners and binding agents in chewing gum.

Bulk sweeteners constitute between 5–95% by weight of the chewing gum,more typically 20–80% by weight of the chewing gum and most commonly30–60% by weight of the chewing gum. Bulk sweeteners may include bothsugar and sugarless sweeteners and components. Sugar sweeteners mayinclude saccharide containing components including but not limited tosucrose, dextrose, maltose, dextrin, dried invert sugar, fructose,levulose, galactose, corn syrup solids, and the like, alone or incombination. Sugarless sweeteners include components with sweeteningcharacteristics but are devoid of the commonly known sugars. Sugarlesssweeteners include but are not limited to sugar alcohols such assorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, maltitol,and the like, alone or in combination.

High intensity sweeteners may also be present and are commonly used withsugarless sweeteners. When used, high intensity sweeteners typicallyconstitute between 0.001–5% by weight of the chewing gum, preferablybetween 0.01–1% by weight of the chewing gum. Typically, high intensitysweeteners are at least 20 times sweeter than sucrose. These may includebut are not limited to sucralose, aspartame, salts of acesulfame,alitame, saccharin and its salts, cyclamic acid and its salts,glycyrrhizin, dihydrochalcones, thaumatin, monellin, and the like, aloneor in combination.

Combinations of sugar and/or sugarless sweeteners may be used in chewinggum. The sweetener may also function in the chewing gum in whole or inpart as a water soluble bulking agent. Additionally, the softener mayprovide additional sweetness such as with aqueous sugar or alditolsolutions.

Flavor should generally be present in the chewing gum in an amountwithin the range of about 0.1–15% by weight of the chewing gum,preferably between about 0.2–5% by weight of the chewing gum, mostpreferably between about 0.5–3% by weight of the chewing gum. Flavoringagents may include essential oils, synthetic flavors or mixtures thereofincluding but not limited to oils derived from plants and fruits such ascitrus oils, fruit essences, peppermint oil, spearmint oil, other mintoils, clove oil, oil of wintergreen, anise and the like. Artificialflavoring agents and components may also be used in the flavoringredient of the invention. Natural and artificial flavoring agents maybe combined in any sensorially acceptable fashion.

Optional ingredients such as colors, emulsifiers, pharmaceutical agentsand additional flavoring agents may also be included in chewing gum.

In accordance with an embodiment of the invention, the gum base andultimate chewing gum product are made continuously in the same mixer.Generally, the gum base portion is made using a mixing L/D of about 25or less, preferably about 20 or less, most preferably about 15 or less.Then, the remaining chewing gum ingredients are combined with the gumbase to make a chewing gum product using a mixing L/D of about 15 orless, preferably about 10 or less, most preferably about 5 or less. Themixing of the gum base ingredients and the remaining chewing gumingredients may occur in different parts of the same mixer or mayoverlap, so long as the total mixing is achieved using an L/D of about40 or less, preferably about 30 or less, most preferably about 20 orless.

When a preferred blade-and-pin mixer is used, having the preferredconfiguration described above, the total chewing gum can be made using amixing L/D of about 19. The gum base can be made using an L/D of about15 or less, and the remaining gum ingredients can be combined with thegum base using a further L/D of about 5 or less.

In order to accomplish the total chewing gum manufacture using thepreferred blade-and-pin mixer 200, it is advantageous to maintain therpm of the mixing screw 120 at less than about 150, preferably less thanabout 100. Also, the mixer temperature is preferably optimized so thatthe gum base is at about 130° F. or lower when it initially meets theother chewing gum ingredients, and the chewing gum product is at about130° F. or lower (preferably 125° F. or lower) when it exits the mixer.This temperature optimization can be accomplished, in part, byselectively heating and/or water cooling the barrel sections surroundingthe mixing zones 220, 230, 240, 250 and 260. However, pursuant to thepresent invention, the temperature optimization can also be accomplishedby adding cooler ingredients to cool the mixer.

In order to manufacture the gum base, the following preferred procedurecan be followed. The elastomer, filler, and at least some of theelastomer solvent are added to the first large feed port 212 in the feedzone 210 of the mixer 200, and are subjected to highly dispersive mixingin the first mixing zone 220 while being conveyed in the direction ofthe arrow 122. The remaining elastomer solvent (if any) and polyvinylacetate are added to the second large feed port 232 in the second mixingzone 230, and the ingredients are subjected to a more distributivemixing in the remainder of the mixing zone 230.

Fats, oils, waxes (if used), emulsifiers and, optionally, colors andantioxidants, are added to the liquid injection ports 241 and 243 in thethird mixing zone 240, and the ingredients are subjected to distributivemixing in the mixing zone 240 while being conveyed in the direction ofthe arrow 122. As noted above, pursuant to the present invention, thefats can be pumped using a diaphragm pump. At this point, the gum basemanufacture should be complete, and the gum base should leave the thirdmixing zone 240 as a substantially homogeneous, lump-free compound witha uniform color.

The fourth mixing zone 250 is used primarily to cool the gum base,although minor ingredient addition may be accomplished. Then, tomanufacture the final chewing gum product, glycerin, corn syrup, otherbulk sugar sweeteners, high intensity sweeteners, and flavors can beadded to the fifth mixing zone 260, and the ingredients are subjected todistributive mixing. If the gum product is to be sugarless, hydrogenatedstarch hydrolyzate or sorbitol solution can be substituted for the cornsyrup and powdered alditols can be substituted for the sugars.

Preferably, glycerin is added to the first liquid injection port 261 inthe fifth mixing zone 260. Solid ingredients (bulk sweeteners,encapsulated high intensity sweeteners, etc.) are added to the largefeed port 262. Syrups (corn syrup, hydrogenated starch hydrolyzate,sorbitol solution, etc.) are added to the next liquid injection port263, and flavors are added to the final liquid injection port 264.Flavors can alternatively be added at ports 261 and 263 in order to helpplasticize the gum base, thereby reducing the temperature and torque onthe screw. This may permit running of the mixer at higher rpm andthroughput. As noted above, pursuant to the present invention, theflavor can be added using a piston pump and the syrups added using agear pump.

The gum ingredients are compounded to a homogeneous mass which isdischarged from the mixer as a continuous stream or “rope”. Thecontinuous stream or rope can be deposited onto a moving conveyor andcarried to a forming station, where the gum is shaped into the desiredform such as by pressing it into sheets, scoring, and cutting intosticks. Because the entire gum manufacturing process is integrated intoa single continuous mixer, there is less variation in the product, andthe product is cleaner and more stable due to its simplified mechanicaland thermal histories.

A wide range of changes and modifications to the preferred embodimentsof the invention will be apparent to persons skilled in the art. Theabove preferred embodiments, and the examples which follow, are merelyillustrative of the invention and should not be construed as imposinglimitations on the invention. For instance, different continuous mixingequipment and different mixer configurations can be used withoutdeparting from the invention as long as the preparation of a chewing gumbase and chewing gum product are accomplished in a single continuousmixer using a mixing L/D of not more than about 40.

EXAMPLE 1 Testing the Suitability of a Continuous Mixer

The following preliminary test can be employed to determine whether aparticular continuous mixer with a particular configuration meets therequirements of a high efficiency mixer suitable for practicing themethod of the invention.

A dry blend of 35.7% butyl rubber (98.5% isobutylene-1.5% isoprenecopolymer, with a molecular weight of 120,000–150,000, manufactured byPolysar, Ltd. of Sarnia, Ontario, Canada as POLYSAR Butyl 101-3); 35.7%calcium carbonate (VICRON 15—15 from Pfizer, Inc., New York, N.Y.);14.3% polyterpene resin (ZONAREZ 90 from Arizona Chemical Company ofPanama City, Fla.) and 14.3% of a second polyterpene resin (ZONAREZ 7125from Arizona Chemical Company) is fed into the continuous mixer inquestion equipped with the mixer configuration to be tested. Thetemperature profile is optimized for the best mixing, subject to therestriction that the exit temperature of the mixture does not exceed170° C. (and preferably remains below 160° C.) to prevent thermaldegradation. In order to qualify as a suitable high efficiency mixer,the mixer should produce a substantially homogeneous, lump-free compoundwith a uniform milky color in not more than about 10 L/D, preferably notmore than about 7 L/D, most preferably not more than about 5 L/D.

To thoroughly check for lumps, the finished rubber compound may bestretched and observed visually, or compressed in a hydraulic press andobserved, or melted on a hot plate, or made into a finished gum basewhich is then tested for lumps using conventional methods.

Also, the mixer must have sufficient length to complete the manufactureof the gum base, and of the chewing gum product, in a single mixer,using a total mixing L/D of not more than about 40. Any mixer whichmeets these requirements falls within the definition of ahigh-efficiency mixer suitable for practicing the method of theinvention.

EXAMPLES 2–11 Continuous Chewing Gum Manufacture

The following examples were run using a Buss kneader with a 100 mm mixerscrew diameter, configured in the preferred manner described above(unless indicated otherwise), with five mixing zones, a total mixing L/Dof 19, and an initial conveying L/D of 1⅓. No die was used at the end ofthe mixer, unless indicated otherwise, and the product mixture exited asa continuous rope. Each example was designed with feed rates to yieldchewing gum product at the rate of 300 pounds per hour.

Liquid ingredients were fed using volumetric pumps into the large feedports and/or smaller liquid injection ports generally positioned asdescribed above, unless otherwise indicated. The pumps wereappropriately sized and adjusted to achieve the desired feed rates.

Dry ingredients were added using gravimetric screw feeders into thelarge addition ports positioned as described above. Again, the feederswere appropriately sized and adjusted to achieve the desired feed rates.

Temperature control was accomplished by circulating fluids throughjackets surrounding each mixing barrel zone and inside the mixing screw.Water cooling was used where temperatures did not exceed 200° F., andoil cooling was used at higher temperatures. Where water cooling wasdesired, tap water (typically at about 57° F.) was used withoutadditional chilling.

Temperatures were recorded for both the fluid and the ingredientmixture. Fluid temperatures were set for each barrel mixing zone(corresponding to zones 220, 230, 240, 250 and 260 in FIGS. 7 and 8),and are reported below as Z1, Z2, Z3, Z4 and Z5, respectively. Fluidtemperatures were also set for the mixing screw 120, and are reportedbelow as S1.

Actual mixture temperatures were recorded near the downstream end ofmixing zones 220, 230, 240 and 250; near the middle of mixing zone 260;and near the end of mixing zone 260. These mixture temperatures arereported below as T1, T2, T3, T4, T5 and T6, respectively. Actualmixture temperatures are influenced by the temperatures of thecirculating fluid, the heat exchange properties of the mixture andsurrounding barrel, and the mechanical heating from the mixing process,and often differ from the set temperatures due to the additionalfactors.

All ingredients were added to the continuous mixer at ambienttemperature (about 77° F.) unless otherwise noted.

EXAMPLE 2

This example illustrates the preparation of a spearmint flavorednon-tack sugar chewing gum. A mixture of 24.2% terpene resin, 29.7%dusted ground butyl rubber (75% rubber with 25% fine ground calciumcarbonate as an anti-blocking aid) and 46.1% fine ground calciumcarbonate was fed at 25 lb/hr into the first large feed port (port 212in FIGS. 7 and 8). Low molecular weight polyisobutylene (mol.wt.=12,000), preheated to 100° C., was also added at 6.3 lb/hr into thisport.

Ground low molecular weight polyvinyl acetate was added at 13.3 lb/hrinto the second large feed port (port 232 in FIGS. 7 and 8).

A fat mixture, preheated to 83° C., was injected into the liquidinjection ports in the third mixing zone (ports 241 and 243 in FIG. 7),at a total rate of 18.4 lb/hr, with 50% of the mixture being fed througheach port. The fat mixture included 30.4% hydrogenated soybean oil,35.4% hydrogenated cottonseed oil, 13.6% partially hydrogenated soybeanoil, 18.6% glycerol monostearate, 1.7% cocoa powder, and 0.2% BHT.

Glycerin was injected into the first liquid injection port in the fifthmixing zone (port 261 in FIG. 7) at 3.9 lb/hr. A mixture of 1.1%sorbitol and 98.9% sugar was added into the large feed port in the fifthmixing zone (port 262 in FIG. 7) at 185.7 lb/hr. Corn syrup, preheatedto 44° C., was added into the second liquid injection port in the fifthmixing zone (port 263 in FIG. 7) at 44.4 lb/hr. Spearmint flavor wasadded into the third liquid injection port in the fifth mixing zone(port 264 in FIG. 7) at 3.0 lb/hr.

The zone temperatures Z1–Z5 were set (in ° F.) at 350, 350, 150, 57 and57, respectively. The mixing screw temperature S1 was set at 120° F. Themixture temperatures T1–T6 were measured at steady state (in ° F.) as235, 209, 177, 101 and 100, and fluctuated slightly during the trial.The screw rotation was 80 rpm.

The chewing gum product exited the mixer at 120° F. The product wascomparable to that produced by conventional pilot scale batchprocessing. The chew was slightly rubbery but no base lumps werevisible.

EXAMPLE 3

This example illustrates the preparation of a peppermint flavorednon-tack sugar chewing gum. A dry mixture of 57% dusted ground butylrubber (75% rubber, 25% calcium carbonate) and 43% fine ground calciumcarbonate was added at the first large feed port 212 (FIG. 7), at 13.9lb/hr. Molten polyisobutylene (preheated to 100° C.) was also added toport 212 at 9.5 lb/hr.

Ground low molecular weight polyvinyl acetate was added to port 232 at13.0 lb/hr.

A fat mixture (preheated to 82° C.) was pumped 50/50 into ports 241 and243 at a total rate of 23.6 lb/hr. The fat mixture included 33.6%hydrogenated cottonseed oil, 33.6% hydrogenated soybean oil, 24.9%partially hydrogenated soybean oil, 6.6% glycerol monostearate, 1.3%cocoa powder and 0.1% BHT. Glycerin was added to port 261 at 2.1 lb/hr.A mixture of 98.6% sugar and 1.4% sorbitol was added to port 262 at 196lb/hr. Corn syrup (preheated to 40° C.) was added to port 263 at 39.9lb/hr. Peppermint flavor was added to port 264 at 2.1 lb/hr.

The zone temperatures (Z1–Z5, ° F.) were set at 350, 350, 300, 60 and60, respectively. The screw temperature (S1) was set at 200° F. Themixture temperatures (T1–T6, ° F.) were measured as 297, 228, 258, 122,98 and 106, respectively. The screw rotation was 85 rpm.

The chewing gum product exited the mixer at 119° F. The finished productwas free of lumps but was dry and lacked tensile strength. These defectswere attributed to the formula rather than the processing.

EXAMPLE 4

This example illustrates the preparation of a spearmint flavored gum forpellet coating. A blend of 27.4% high molecular weight terpene resin,26.9% low molecular weight terpene resin, 28.6% dusted ground butylrubber (75% rubber, 25% calcium carbonate) and 17.1% fine ground calciumcarbonate was fed into the first large port 212 (FIG. 7), at 33.5 lb/hr.Molten polyisobutylene (100° C.) was pumped into the same port at 1.3lb/hr.

Low molecular weight polyvinyl acetate was fed to port 232 at 19.8lb/hr.

A fat mixture (82° C.) was added 50/50 into ports 241 and 243, at atotal rate of 17.4 lb/hr. The fat mixture included 22.6% hydrogenatedcottonseed oil, 21.0% partially hydrogenated soybean oil, 21.0%hydrogenated soybean oil, 19.9% glycerol monostearate, 15.4% lecithinand 0.2% BHT.

Sugar was fed into port 262 at 157.8 lb/hr. Corn syrup (40° C.) wasadded to port 263 at 68.4 lb/hr. Spearmint flavor was added to port 264at 1.8 lb/hr.

The zone temperatures (Z1–Z5, ° F.) were set at 160, 160, 110, 60 and60, respectively. The screw temperature (S1) was set at 68° F. Themixture temperatures (T1–T6, ° F.) were measured as 230, 215, 166, 105,109 and 111, respectively. The screw rotation was 80 rpm.

The chewing gum product exited the mixer at 121° F. The product was firmand cohesive when chewed (normal for a pellet center). No base lumpswere visible.

EXAMPLE 5

This example illustrates the preparation of a peppermint flavored sugarchewing gum. A blend of 24.4% dusted ground butyl rubber (75% rubber,25% calcium carbonate), 18.0% low molecular weight terpene resin, 18.3%high molecular weight terpene resin and 39.4% fine ground calciumcarbonate was added to the first large port 212 (FIG. 7) at 27.6 lb/hr.

A blend of 11.1% high molecular weight polyvinyl acetate and 88.9% lowmolecular weight polyvinyl acetate was added into the second large feedport 232 at 14.4 lb/hr. Polyisobutylene (preheated to 100° C.) was alsoadded to this port at 3.5 lb/hr.

A fat mixture (83° C.) was added 50/50 into ports 241 and 243, at atotal rate of 14.5 lb/hr. This fat mixture included 31.9% hydrogenatedcottonseed oil, 18.7% hydrogenated soybean oil, 13.2% partiallyhydrogenated cottonseed oil, 19.8% glycerol monostearate, 13.7% soylecithin, 2.5% cocoa powder and 0.2% BHT.

Glycerin was injected into port 261 at 3.9 lb/hr. A mixture of 84.6%sucrose and 15.4% dextrose monohydrate was added to port 262 at 203.1lb/hr. Corn syrup (40° C.) was injected into port 263 at 30.0 lb/hr. Amixture of 90% peppermint flavor and 10% soy lecithin was injected intoport 264 at 3.0 lb/hr.

The zone temperatures (Z1–Z5, ° F.) were set at 350, 350, 100, 60 and60, respectively, and the screw temperature (S1) was set at 100° F. Themixture temperatures (T1–T6, ° F.) were measured as 308, 261, 154, 95,94 and 105, respectively. The screw rotation was set at 55 rpm.

The product exited the mixer at 127° F. The finished product had goodchew characteristics and there was no evidence of rubber lumps.

EXAMPLE 6

This example illustrates the preparation of a fruit-flavored sugar gum.A mixture of 39.3% dusted ground butyl rubber (75% rubber, 25% calciumcarbonate), 39.1% low molecular weight terpene resin and 21.6% fineground calcium carbonate was added to the first large feed port 212(FIG. 7) at 20.6 lb/hr.

A mixture of 33.0% low molecular weight terpene resin and 67.0% lowmolecular weight polyvinyl acetate was added at 24.4 lb/hr into thesecond large feed port 232. Polyisobutylene (preheated to 100° C.) wasalso added at 1.0 lb/hr into the port 232.

A fat/wax composition (82° C.) was injected 50/50 into the liquidinjection ports 241 and 243, at a total rate of 0.14.0 lb/hr. Thecomposition included 29.7% paraffin wax, 21.7% microcrystalline wax(m.p.=170° F.), 5.7% microcrystalline wax (m.p.=180° F.), 20.5% glycerolmonostearate, 8.6% hydrogenated cottonseed oil, 11.4% soy lecithin, 2.1%cocoa powder, and 0.3% BHT.

Glycerin was injected into the liquid injection port 261 at 3.3 lb/hr. Amixture of 88.5% sucrose and 11.5% dextrose monohydrate was added at201.0 lb/hr into the large port 262. Corn syrup (40° C.) was injected at3.0 lb/hr into the liquid injection port 263, and a mixture of 88.9%fruit flavor and 11.1% soy lecithin was injected at 2.7 lb/hr into theliquid injection port 264.

The zone temperatures (Z1–Z5, ° F.) were set at 425, 425, 200, 61 and61, respectively. The screw temperature (S1) was set at 66° F. Themixture temperatures (T1–T6, ° F.) were measured as 359, 278, 185, 105,100 and 109, respectively. The screw rotation was set at 70 rpm.

The chewing gum product exited the mixer at 122° F. The product was verysoft while warm and fell apart during chewing. However, this was notatypical for this product. After aging for two months, the product wasagain chewed and found to have excellent texture and flavor. No rubberlumps were visible.

EXAMPLE 7

This example illustrates the preparation of a sugar chunk bubble gum.For this example, the mixer configuration was varied slightly from thepreferred configuration described above and used for Examples 2–6.Specifically, a round-hole 30 mm die was installed at the exit end ofthe mixer.

A blend of 68.9% high molecular weight polyvinyl acetate and 31.1%ground talc was added into the first large feed port 212 (FIG. 7), at35.4 lb/hr. Polyisobutylene (preheated to 100° C.) was also added toport 212 at 3.95 lb/hr. Further downstream, in the first mixing zone220, acetylated monoglyceride was injected at 2.6 lb/hr, using a liquidinjection (hollow barrel pin) port not shown in FIG. 7.

Additional polyisobutylene (100° C.) at 3.95 lb/hr, and glycerol esterof partially hydrogenated wood rosin at 13.4 lb/hr, were added into thesecond large port 232. A mixture of 43.6% glycerol monostearate, 55.9%triacetin and 0.5% BHT was added at 6.7 lb/hr into the liquid injectionport 241.

Glycerin was injected at 2.1 lb/hr into the liquid injection port 261. Amixture of 98.4% sucrose and 1.6% citric acid was added at 170.4 lb/hrinto the large port 262. Corn syrup (40° C.) was injected at 58.5 lb/hrinto liquid injection port 263, and a mixture of 60% lemon-lime flavorand 40% soy lecithin was added at 3.0 lb/hr into the liquid injectionport 264.

The zone temperatures (Z1–Z5, ° F.) were ultimately set at 440, 440,160, 61 and 61, respectively. The screw temperature (S1) was ultimatelyset at 80° F. The mixture temperatures (T1–T6, ° F.) were ultimatelymeasured as 189, 176, 161, 97, 108 and 112, respectively. The screwrotation was 55 rpm.

At first, the product exited the extruder at 140° F. and exhibited signsof heat stress. The zone temperatures Z1 and Z2 were then reduced by 10°F. each, and the screw temperature S1 was raised by 20° F., to thevalues shown above. This caused the chewing gum exit temperature to dropto 122° F., and the product quality improved markedly.

During chewing, the product exhibited excellent texture, flavor, andbubble blowing characteristics. No rubber lumps were visible.

EXAMPLE 8

This example illustrates the preparation of a spearmint flavoredsugarless gum. A mixture of 42.1% fine ground calcium carbonate, 18.9%glycerol ester of wood rosin, 16.7% glycerol ester of partiallyhydrogenated wood rosin, 17.0% ground butyl rubber, and 5.3% dustedground (25:75) styrene butadiene rubber (75% rubber, 25% calciumcarbonate) was added into port 212 (FIG. 7) at 38.4 lb/hr.

Low molecular weight polyvinyl acetate at 12.7 lb/hr, andpolyisobutylene (preheated to 100° C.) at 7.6 lb/hr, were added intoport 232.

A fat mixture (82° C.) was injected 50/50 into ports 241 and 243, at atotal rate of 20.9 lb/hr. The fat mixture included 35.7% hydrogenatedcottonseed oil, 30.7% hydrogenated soybean oil, 20.6% partiallyhydrogenated soybean oil, 12.8% glycerol monostearate and 0.2% BHT.

Unlike the previous examples, glycerin was injected at 25.5 lb/hr intothe fourth mixing zone 250 (FIG. 7) through a liquid injection port (notshown). A coevaporated blend of hydrogenated starch hydrolysate andglycerin (at 40° C.) was injected further downstream in the fourthmixing zone 250 through another liquid injection port (not shown). Thecoevaporated blend included 67.5% hydrogenated starch hydrolysatesolids, 25% glycerin and 7.5% water.

A mixture of 84.8% sorbitol, 14.8% mannitol and 0.4% encapsulatedaspartame was added into port 262 in the fifth mixing zone 260, at 162.3lb/hr. A mixture of 94.1% spearmint flavor and 5.9% lecithin wasinjected at 5.1 lb/hr into the port 264 located further downstream.

The zone temperatures (Z1–Z5, ° F.) were set at 400, 400, 150, 62 and62, respectively. The screw temperature (S1) was set at 66° F. Themixture temperatures (T1–T6, ° F) were measured as 307, 271, 202, 118,103 and 116. The mixing screw rotation was 69 rpm.

The chewing gum product exited the mixer at 117° F. The gum had goodappearance with no sorbitol spots or rubber lumps. The gum was slightlywet to the touch, sticky and fluffy (low density), but was acceptable.During chewing, the gum was considered soft initially but firmed up withcontinued chewing.

EXAMPLE 9

This example illustrates the preparation of a sugarless spearmint gumfor use in coated pellets. A mixture of 28.6% dusted ground butyl rubber(75% rubber, 25% calcium carbonate), 27.4% high molecular weight terpeneresin, 26.9% low molecular weight terpene resin and 17.1% calciumcarbonate was added into port 212 (FIG. 7) at 41.9 lb/hr.

Low molecular weight polyvinyl acetate at 24.7 lb/hr, andpolyisobutylene (preheated to 100° C.) at 1.7 lb/hr, were added intoport 232.

A fat composition (82° C.) was injected 50/50 into ports 241 and 243 ata total rate of 21.7 lb/hr. The fat composition included 22.6%hydrogenated cottonseed oil, 21.0% hydrogenated soybean oil, 21.0%partially hydrogenated soybean oil, 19.9% glycerol monostearate, 15.4%glycerin and 0.2% BHT.

A 70% sorbitol solution was injected into the fourth mixing zone 250(FIG. 7) at 17.4 lb/hr, using a hollow barrel pin liquid injection port(not shown).

A mixture of 65.8% sorbitol, 17.9% precipitated calcium carbonate and16.3% mannitol was added at 184.2 lb/hr into the final large port 262. Amixture of 71.4% spearmint flavor and 28.6% soy lecithin was added at8.4 lb/hr into the final liquid injection port 264.

The zone temperatures (Z1–Z5, ° F.) were set at 400, 400, 150, 61 and61, respectively. The screw temperature (S1) was set at 65° F. Themixture temperatures (T1–T6, ° F.) were measured as 315, 280, 183, 104,109 and 116, respectively. The screw rotation was set at 61 rpm.

The chewing gum exited the mixer at 127° F. The product appearance wasgood with no sorbitol spots or rubber lumps. However, the initial chewwas reported as being rough and grainy.

EXAMPLE 10

This example illustrates the preparation of a peppermint flavored sugarchewing gum. A mixture of 27.4% dusted ground butyl rubber (75% butylrubber dusted with 25% calcium carbonate), 14.1% lower softening terpeneresin (softening point=85° C.), 14.4% higher softening terpene resin(softening point=125° C.) and 44.1% calcium carbonate was fed at 24.6lb/hr into the first large feed port (port 212 in FIGS. 7 and 8).

A mixture of 73.5% low molecular weight polyvinyl acetate, 9.2% highmolecular weight polyvinyl acetate, 8.6 lower softening terpene resinand 8.7% higher softening terpene resin was fed at 17.4 lb/hr into thesecond large feed port 232. Polyisobutylene was also added at 3.5 lb/hrinto this port.

A fat mixture, preheated to 83° C., was injected into the liquidinjection ports in the third mixing zone (ports 241 and 243 in FIG. 7),at a total rate of 14.5 lb/hr, with 50% of the mixture being fed througheach port. The fat mixture included 0.2% BHT, 2.5% cocoa powder, 31.9%hydrogenated cottonseed oil, 19.8% glycerol monostearate, 18.7%hydrogenated soybean oil, 13.7% lecithin, and 13.2% partiallyhydrogenated cottonseed oil.

A mixture of 84.6% sugar and 15.4% dextrose monohydrate was injected at203.1 lb/hr into the large feed port 262 in the fifth mixing zone.Glycerin was added at 3.9 lb/hr into the first liquid injection port 261in the fifth mixing zone. Corn syrup, preheated to 44° C., was added at30.0 lb/hr into the second liquid injection port 263 in the fifth mixingzone. A mixture of 90.0% peppermint flavor and 10.0% lecithin wasinjected into the third liquid injection port 264 in the fifth mixingzone at 3.0 lb/hr.

The zone temperatures Z1–Z5 were set (in ° F.) at 350, 350, 110, 25 and25, respectively. The mixing screw temperature S1 was set at 101° F. Themixer temperatures T1–T6 were measured at steady state (in ° F.) as 320,280, 164, 122, 105 and 103, respectively. The screw rotation was 63 rpm,and the product exited the mixer at 52–53° C.

The peppermint sugar gum product was desirably soft, and acceptable inquality.

EXAMPLE 11

This example illustrates the preparation of a sugarless stick bubblegum. For this example, the screw configuration shown in FIG. 8, and usedfor the previous examples, was varied as follows. The conveying section210 and mixing sections 220, 250 and 260 were configured substantiallyas before. In the second mixing zone 230, the three low shear elements40 were also not changed.

Thereafter, the 1½ high shear elements 50 in zone 230, the restrictionelement 30 overlapping zones 230 and 240, all of zone 240, and therestriction element 30 overlapping zones 240 and 250 were removed. Threehigh shear elements 50 (combined L/D=2.0) were placed in zone 230 andextended into zone 240. Two and one-half low shear elements 40 (combinedL/D=1⅔) followed in zone 240. Then, three and one-half high shearelements 50 (combined L/D=2⅓) followed in zone 240 and extended intozone 250. The eleven low-shear elements 40 in zones 250 and 260 were notchanged.

To make the product, a mixture of 53.3% high molecular weight polyvinylacetate, 31.0% talc, 12.2% glycerol ester of wood rosin and 3.5% dustedground (25:75) styrene-butadiene rubber (75% rubber, 25% calciumcarbonate) were fed into the large port 212 (FIG. 7) at 54.9 lb/hr.Polyisobutylene (preheated to 100° C.) was pumped into the same port at9.0 lb/hr.

Glycerol ester of partially hydrogenated wood rosin at 15.3 lb/hr, andtriacetin at 4.4 lb/hr, were added into the large port 232 in the secondmixing zone 230.

A fat/wax mixture (at 82° C.) was fed 50/50 into the liquid injectionports 241 and 243 in the third mixing zone 240, at a total rate of 13.9lb/hr. The mixture included 50.3% glycerol monostearate, 49.4% paraffin(m.p.=135° F.) and 0.3% BHT.

Diluted glycerin was injected into the fourth mixing zone 250 at 28.2lb/hr using a liquid injection port (not shown). The dilution was 87%glycerin and 13% water.

A mixture of 84.0% sorbitol, 12.7% mannitol, 1.1% fumaric acid, 0.2%aspartame, 0.4% encapsulated aspartame, 0.7% adipic acid and 0.9% citricacid was fed into port 262 in the fifth mixing zone 260 at 165.0 lb/hr.A mixture of 51.6% bubble gum flavor and 48.4% soy lecithin was injectedinto port 264 in zone 260 at 9.3 lb/hr.

The zone temperatures (Z1–Z5, ° F.) were set at 350, 350, 100, 64 and64, respectively. The screw temperature (S1) was set at 100° F. Themixture temperatures (T1–T6, ° F.) were recorded as 286, 260, 163, 107,104 and 112, respectively. The screw rotation was 75 rpm.

The chewing gum exited the mixer at 118° F. The finished product lookedgood and contained no base lumps. The flavor and texture were very goodduring chewing, as were the bubble blowing characteristics.

By way of example, and not limitation, Examples 12–13 are directed tothe methods of optimizing the ingredient addition openings of theextruder.

EXAMPLE 12

Several premix compositions were prepared to simplify the mixingprocess.

Rubber Blend

Three parts butyl rubber were ground with one part calcium carbonate.35.611% of the ground mixture was dry blended with 55.746% calciumcarbonate and 8.643% glycerol ester of hydrogenated rosin.

Polyvinyl Acetate Blend

43.618% low molecular weight PVAc was melted and blended with 10.673%glycerol ester of polymerized rosin and 45.709% glycerol ester ofhydrogenated rosin.

Fat Blend

The following ingredients were melted and blended:

-   -   7.992% hydrogenated soybean oil    -   13.712% hydrogenated cottonseed oil    -   12.199% glycerol monostearate    -   37.070% paraffin wax    -   28.851% microcrystalline wax    -   0.176% BHT        Corn Syrup/Glycerin Blend

93.713% 45.5 Baume corn syrup was heated and blended with 6.287%glycerin.

Sugar/Color Blend

10% of a glycerin slurry of red lake was mixed with 90% sugar in aHobart mixer. The resulting product was a damp powder which could be fedinto the extruder with a twin screw volumetric feeder.

To the first port were added the rubber blend (34.67 lbs/hr) and moltenpolyisobutylene (5.80 lbs/hr). The opening in the injection pin whichinjects polyisobutylene is ⅜ of an inch in diameter.

Into the second port was added the polyvinyl acetate blend at 24.98lbs/hr.

Molten fat blend was injected in equal portions through two injectionpins with openings of 2 mm in diameter, in section 3 at a total rate of26.98 lbs/hr.

Heated corn syrup/glycerin blend was injected through a pin, with anopening of 3/16 of an inch in diameter, located at the beginning ofsection 5 at a rate of 78.92 lbs/hr.

Sugar was added into port 5 at a rate of 283.15 lbs/hr along with thesugar/color blend at 13.87 lbs/hr.

Finally, cinnamon flavor was injected, through an opening of 2 mm indiameter, near the end of section 5 at a rate of 6.62 lbs/hr.

This produces a total output of approximately 475 lbs/hr from theextruder.

The zone temperatures (Z1–Z5 in ° F.) were set to 350, 250, 150, 55 and55. The screw was heated to 150° F., and run at 115 rpm.

The screw was configured as follows:

In the first barrel section, four low shear then two high shear elementshaving a total L/D of 4 were fitted to the screw shaft. Straddling theend of the first section and the beginning of the second was a 57 mmrestriction ring which, along with its on-screw hardware, was a L/D of1.

In the second section, three low shear elements then 1½ high shearelements having a total L/D of 3 were fitted. Straddling the end of thesecond section and beginning of the third was a 60 mm restriction ring(1 L/D).

In the third section was fitted 4½ high shear elements (3½ L/D). A 60 mmrestriction ring (1 L/D) straddles the third and fourth sections.

The fourth section was fitted with five low shear elements (3⅓ L/D) andone conveyor element (1 L/D) which extends into the fifth section.

The fifth section was fitted with a second conveyor element having anL/D of 1. This was followed by 3 low shear elements having a total L/Dof 2. the total screw length was 20⅓ L/D.

With this configuration, it was necessary to operate the screw at 125rpm in order to prevent a backup of sugar in the fifth intake port.

EXAMPLE 13

Although the run described in Example 12 was generally acceptable, therewas a minor problem with incorporated sugar as evidenced by anoccasional puff of sugar dust from the extruder discharge. This wasremedied by the following changes.

A low shear half element in Section 4 was removed. The two conveyorelements were moved upstream to fill the gap created by removal of thehalf element. An additional low shear half element was added after theconveyor elements to increase mixing. The corn syrup/glycerin blendinjection point was moved to a pin located after port 5.

The screw speed was reduced to 109 rpm. The finished product exited at122° F.

In summary, the foregoing examples indicate that the method of theinvention can be used to prepare a wide variety of good quality chewinggum products in a continuous mixer. This method is expected to savemanufacturing time and money, and improve the product consistency andquality. It should be appreciated that the method of the presentinvention is capable of being incorporated in the form of a variety ofembodiments, only a few of which have been illustrated and describedabove. The invention may be embodied in other forms without departingfrom its spirit or essential characteristics. It will be appreciatedthat the addition of certain other ingredients, process steps, materialsor components not specifically included will have an adverse impact onthe present invention. The best mode of the invention may thereforeexclude ingredients, process steps, materials or components other thanthose listed above for inclusion or use in the invention. However, thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive, and the scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

1. A method for manufacturing chewing gum using a high efficiencycontinuous mixer comprising the steps of: providing a high efficiencycontinuous mixer that includes ingredient addition ports havingopenings; enlarging at least one of the openings of one of theingredient addition ports by at least 10% and to no more than 95%greater than the size of a similar standard opening size; adding gumbase ingredients to the mixer; adding flavor and sweetener to the mixer;and at least one of the ingredients is added through the enlargedopening.
 2. The method of claim 1 wherein the gum base is added asfinished gum base to the mixer.
 3. The method of claim 1 wherein theopening is enlarged sufficiently to allow the ingredient to be addedwithout the ingredient being heated.
 4. The method of claim 1 whereinthe opening of a feed nozzle is enlarged.
 5. The method of claim 1wherein the opening of an injection port is enlarged.
 6. A method ofcontinuously manufacturing chewing gum without requiring separatemanufacture of a chewing gum base, comprising the steps of: a) adding atleast an elastomer and filler into a high efficiency continuous mixer;b) adding at least one sweetener and at least one favoring agent intothe elastomer and filler in the continuous mixer; and c) wherein atleast one ingredient is added through an opening that has been enlargedby at least 10% and no more than 95% as compared to a similar standardopening.
 7. The method of claim 6 wherein the opening is enlargedsufficiently to allow the ingredient to be added without the ingredientbeing heated.
 8. The method of claim 6 wherein the opening of a feednozzle is enlarged.
 9. The method of claim 6 wherein the opening of aninjection port is enlarged.